PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus which uniformizes noises.SOLUTION: An X-ray CT apparatus includes an X-ray tube, a high voltage generator, photon counting detectors PCD1-PCDN, an acquisition part and an adjustment part. The X-ray tube generates X-rays. The high voltage generator generates tube voltages applied on the X-ray tube. The photon counting detectors PCD1-PCDN output signals in accordance with incidence of the photon of the X-rays. The acquisition part acquires the photon counting value of the X-rays transmitted through the subject using the signals in each of the plurality of energy bands. The adjustment part adjusts at least one of threshold values partitioning the plurality of energy bands in accordance with the tube voltage.SELECTED DRAWING: Figure 1【課題】ノイズを均一化するＸ線ＣＴ装置を提供する。【解決手段】Ｘ線ＣＴ装置は、Ｘ線管と、高電圧発生器と、光子計数検出器ＰＣＤ１～ＰＣＤＮと、取得部と、調整部とを備える。Ｘ線管は、Ｘ線を発生させる。高電圧発生器は、Ｘ線管に印加される管電圧を発生させる。光子計数検出器ＰＣＤ１～ＰＣＤＮは、Ｘ線の光子の入射に応じて信号を出力する。取得部は、信号を用いて、被検体を透過したＸ線の光子の計数値を、複数のエネルギー帯域ごとに取得する。調整部は、管電圧に応じて、複数のエネルギー帯域を区分する閾値のうち少なくとも一つを調整する。【選択図】図１
